1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright IBM Corp. 2000, 2006
4 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
5 * Gerhard Tonn (ton@de.ibm.com)
6 *
7 * Copyright (C) 1991, 1992 Linus Torvalds
8 *
9 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
10 */
11
12 #include <linux/compat.h>
13 #include <linux/sched.h>
14 #include <linux/sched/task_stack.h>
15 #include <linux/mm.h>
16 #include <linux/smp.h>
17 #include <linux/kernel.h>
18 #include <linux/signal.h>
19 #include <linux/errno.h>
20 #include <linux/wait.h>
21 #include <linux/ptrace.h>
22 #include <linux/unistd.h>
23 #include <linux/stddef.h>
24 #include <linux/tty.h>
25 #include <linux/personality.h>
26 #include <linux/binfmts.h>
27 #include <asm/ucontext.h>
28 #include <linux/uaccess.h>
29 #include <asm/lowcore.h>
30 #include <asm/switch_to.h>
31 #include "compat_linux.h"
32 #include "compat_ptrace.h"
33 #include "entry.h"
34
35 typedef struct
36 {
37 __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
38 struct sigcontext32 sc;
39 _sigregs32 sregs;
40 int signo;
41 _sigregs_ext32 sregs_ext;
42 __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
43 } sigframe32;
44
45 typedef struct
46 {
47 __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
48 __u16 svc_insn;
49 compat_siginfo_t info;
50 struct ucontext32 uc;
51 } rt_sigframe32;
52
53 /* Store registers needed to create the signal frame */
store_sigregs(void)54 static void store_sigregs(void)
55 {
56 save_access_regs(current->thread.acrs);
57 save_fpu_regs();
58 }
59
60 /* Load registers after signal return */
load_sigregs(void)61 static void load_sigregs(void)
62 {
63 restore_access_regs(current->thread.acrs);
64 }
65
save_sigregs32(struct pt_regs * regs,_sigregs32 __user * sregs)66 static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
67 {
68 _sigregs32 user_sregs;
69 int i;
70
71 user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32);
72 user_sregs.regs.psw.mask &= PSW32_MASK_USER | PSW32_MASK_RI;
73 user_sregs.regs.psw.mask |= PSW32_USER_BITS;
74 user_sregs.regs.psw.addr = (__u32) regs->psw.addr |
75 (__u32)(regs->psw.mask & PSW_MASK_BA);
76 for (i = 0; i < NUM_GPRS; i++)
77 user_sregs.regs.gprs[i] = (__u32) regs->gprs[i];
78 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
79 sizeof(user_sregs.regs.acrs));
80 fpregs_store((_s390_fp_regs *) &user_sregs.fpregs, ¤t->thread.fpu);
81 if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32)))
82 return -EFAULT;
83 return 0;
84 }
85
restore_sigregs32(struct pt_regs * regs,_sigregs32 __user * sregs)86 static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
87 {
88 _sigregs32 user_sregs;
89 int i;
90
91 /* Alwys make any pending restarted system call return -EINTR */
92 current->restart_block.fn = do_no_restart_syscall;
93
94 if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
95 return -EFAULT;
96
97 if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
98 return -EINVAL;
99
100 /* Test the floating-point-control word. */
101 if (test_fp_ctl(user_sregs.fpregs.fpc))
102 return -EINVAL;
103
104 /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
105 regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
106 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
107 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 |
108 (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
109 /* Check for invalid user address space control. */
110 if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
111 regs->psw.mask = PSW_ASC_PRIMARY |
112 (regs->psw.mask & ~PSW_MASK_ASC);
113 regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
114 for (i = 0; i < NUM_GPRS; i++)
115 regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
116 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
117 sizeof(current->thread.acrs));
118 fpregs_load((_s390_fp_regs *) &user_sregs.fpregs, ¤t->thread.fpu);
119
120 clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
121 clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
122 return 0;
123 }
124
save_sigregs_ext32(struct pt_regs * regs,_sigregs_ext32 __user * sregs_ext)125 static int save_sigregs_ext32(struct pt_regs *regs,
126 _sigregs_ext32 __user *sregs_ext)
127 {
128 __u32 gprs_high[NUM_GPRS];
129 __u64 vxrs[__NUM_VXRS_LOW];
130 int i;
131
132 /* Save high gprs to signal stack */
133 for (i = 0; i < NUM_GPRS; i++)
134 gprs_high[i] = regs->gprs[i] >> 32;
135 if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high,
136 sizeof(sregs_ext->gprs_high)))
137 return -EFAULT;
138
139 /* Save vector registers to signal stack */
140 if (MACHINE_HAS_VX) {
141 for (i = 0; i < __NUM_VXRS_LOW; i++)
142 vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
143 if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
144 sizeof(sregs_ext->vxrs_low)) ||
145 __copy_to_user(&sregs_ext->vxrs_high,
146 current->thread.fpu.vxrs + __NUM_VXRS_LOW,
147 sizeof(sregs_ext->vxrs_high)))
148 return -EFAULT;
149 }
150 return 0;
151 }
152
restore_sigregs_ext32(struct pt_regs * regs,_sigregs_ext32 __user * sregs_ext)153 static int restore_sigregs_ext32(struct pt_regs *regs,
154 _sigregs_ext32 __user *sregs_ext)
155 {
156 __u32 gprs_high[NUM_GPRS];
157 __u64 vxrs[__NUM_VXRS_LOW];
158 int i;
159
160 /* Restore high gprs from signal stack */
161 if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high,
162 sizeof(sregs_ext->gprs_high)))
163 return -EFAULT;
164 for (i = 0; i < NUM_GPRS; i++)
165 *(__u32 *)®s->gprs[i] = gprs_high[i];
166
167 /* Restore vector registers from signal stack */
168 if (MACHINE_HAS_VX) {
169 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
170 sizeof(sregs_ext->vxrs_low)) ||
171 __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
172 &sregs_ext->vxrs_high,
173 sizeof(sregs_ext->vxrs_high)))
174 return -EFAULT;
175 for (i = 0; i < __NUM_VXRS_LOW; i++)
176 *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
177 }
178 return 0;
179 }
180
COMPAT_SYSCALL_DEFINE0(sigreturn)181 COMPAT_SYSCALL_DEFINE0(sigreturn)
182 {
183 struct pt_regs *regs = task_pt_regs(current);
184 sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
185 sigset_t set;
186
187 if (get_compat_sigset(&set, (compat_sigset_t __user *)frame->sc.oldmask))
188 goto badframe;
189 set_current_blocked(&set);
190 save_fpu_regs();
191 if (restore_sigregs32(regs, &frame->sregs))
192 goto badframe;
193 if (restore_sigregs_ext32(regs, &frame->sregs_ext))
194 goto badframe;
195 load_sigregs();
196 return regs->gprs[2];
197 badframe:
198 force_sig(SIGSEGV);
199 return 0;
200 }
201
COMPAT_SYSCALL_DEFINE0(rt_sigreturn)202 COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
203 {
204 struct pt_regs *regs = task_pt_regs(current);
205 rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
206 sigset_t set;
207
208 if (get_compat_sigset(&set, &frame->uc.uc_sigmask))
209 goto badframe;
210 set_current_blocked(&set);
211 if (compat_restore_altstack(&frame->uc.uc_stack))
212 goto badframe;
213 save_fpu_regs();
214 if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
215 goto badframe;
216 if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
217 goto badframe;
218 load_sigregs();
219 return regs->gprs[2];
220 badframe:
221 force_sig(SIGSEGV);
222 return 0;
223 }
224
225 /*
226 * Set up a signal frame.
227 */
228
229
230 /*
231 * Determine which stack to use..
232 */
233 static inline void __user *
get_sigframe(struct k_sigaction * ka,struct pt_regs * regs,size_t frame_size)234 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
235 {
236 unsigned long sp;
237
238 /* Default to using normal stack */
239 sp = (unsigned long) A(regs->gprs[15]);
240
241 /* Overflow on alternate signal stack gives SIGSEGV. */
242 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
243 return (void __user *) -1UL;
244
245 /* This is the X/Open sanctioned signal stack switching. */
246 if (ka->sa.sa_flags & SA_ONSTACK) {
247 if (! sas_ss_flags(sp))
248 sp = current->sas_ss_sp + current->sas_ss_size;
249 }
250
251 return (void __user *)((sp - frame_size) & -8ul);
252 }
253
setup_frame32(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)254 static int setup_frame32(struct ksignal *ksig, sigset_t *set,
255 struct pt_regs *regs)
256 {
257 int sig = ksig->sig;
258 sigframe32 __user *frame;
259 unsigned long restorer;
260 size_t frame_size;
261
262 /*
263 * gprs_high are always present for 31-bit compat tasks.
264 * The space for vector registers is only allocated if
265 * the machine supports it
266 */
267 frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved);
268 if (!MACHINE_HAS_VX)
269 frame_size -= sizeof(frame->sregs_ext.vxrs_low) +
270 sizeof(frame->sregs_ext.vxrs_high);
271 frame = get_sigframe(&ksig->ka, regs, frame_size);
272 if (frame == (void __user *) -1UL)
273 return -EFAULT;
274
275 /* Set up backchain. */
276 if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
277 return -EFAULT;
278
279 /* Create struct sigcontext32 on the signal stack */
280 if (put_compat_sigset((compat_sigset_t __user *)frame->sc.oldmask,
281 set, sizeof(compat_sigset_t)))
282 return -EFAULT;
283 if (__put_user(ptr_to_compat(&frame->sregs), &frame->sc.sregs))
284 return -EFAULT;
285
286 /* Store registers needed to create the signal frame */
287 store_sigregs();
288
289 /* Create _sigregs32 on the signal stack */
290 if (save_sigregs32(regs, &frame->sregs))
291 return -EFAULT;
292
293 /* Place signal number on stack to allow backtrace from handler. */
294 if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
295 return -EFAULT;
296
297 /* Create _sigregs_ext32 on the signal stack */
298 if (save_sigregs_ext32(regs, &frame->sregs_ext))
299 return -EFAULT;
300
301 /* Set up to return from userspace. If provided, use a stub
302 already in userspace. */
303 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
304 restorer = (unsigned long __force)
305 ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
306 } else {
307 /* Signal frames without vectors registers are short ! */
308 __u16 __user *svc = (void __user *) frame + frame_size - 2;
309 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
310 return -EFAULT;
311 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
312 }
313
314 /* Set up registers for signal handler */
315 regs->gprs[14] = restorer;
316 regs->gprs[15] = (__force __u64) frame;
317 /* Force 31 bit amode and default user address space control. */
318 regs->psw.mask = PSW_MASK_BA |
319 (PSW_USER_BITS & PSW_MASK_ASC) |
320 (regs->psw.mask & ~PSW_MASK_ASC);
321 regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler;
322
323 regs->gprs[2] = sig;
324 regs->gprs[3] = (__force __u64) &frame->sc;
325
326 /* We forgot to include these in the sigcontext.
327 To avoid breaking binary compatibility, they are passed as args. */
328 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
329 sig == SIGTRAP || sig == SIGFPE) {
330 /* set extra registers only for synchronous signals */
331 regs->gprs[4] = regs->int_code & 127;
332 regs->gprs[5] = regs->int_parm_long;
333 regs->gprs[6] = current->thread.last_break;
334 }
335
336 return 0;
337 }
338
setup_rt_frame32(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)339 static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set,
340 struct pt_regs *regs)
341 {
342 rt_sigframe32 __user *frame;
343 unsigned long restorer;
344 size_t frame_size;
345 u32 uc_flags;
346
347 frame_size = sizeof(*frame) -
348 sizeof(frame->uc.uc_mcontext_ext.__reserved);
349 /*
350 * gprs_high are always present for 31-bit compat tasks.
351 * The space for vector registers is only allocated if
352 * the machine supports it
353 */
354 uc_flags = UC_GPRS_HIGH;
355 if (MACHINE_HAS_VX) {
356 uc_flags |= UC_VXRS;
357 } else
358 frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) +
359 sizeof(frame->uc.uc_mcontext_ext.vxrs_high);
360 frame = get_sigframe(&ksig->ka, regs, frame_size);
361 if (frame == (void __user *) -1UL)
362 return -EFAULT;
363
364 /* Set up backchain. */
365 if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
366 return -EFAULT;
367
368 /* Set up to return from userspace. If provided, use a stub
369 already in userspace. */
370 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
371 restorer = (unsigned long __force)
372 ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
373 } else {
374 __u16 __user *svc = &frame->svc_insn;
375 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
376 return -EFAULT;
377 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
378 }
379
380 /* Create siginfo on the signal stack */
381 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
382 return -EFAULT;
383
384 /* Store registers needed to create the signal frame */
385 store_sigregs();
386
387 /* Create ucontext on the signal stack. */
388 if (__put_user(uc_flags, &frame->uc.uc_flags) ||
389 __put_user(0, &frame->uc.uc_link) ||
390 __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
391 save_sigregs32(regs, &frame->uc.uc_mcontext) ||
392 put_compat_sigset(&frame->uc.uc_sigmask, set, sizeof(compat_sigset_t)) ||
393 save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
394 return -EFAULT;
395
396 /* Set up registers for signal handler */
397 regs->gprs[14] = restorer;
398 regs->gprs[15] = (__force __u64) frame;
399 /* Force 31 bit amode and default user address space control. */
400 regs->psw.mask = PSW_MASK_BA |
401 (PSW_USER_BITS & PSW_MASK_ASC) |
402 (regs->psw.mask & ~PSW_MASK_ASC);
403 regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler;
404
405 regs->gprs[2] = ksig->sig;
406 regs->gprs[3] = (__force __u64) &frame->info;
407 regs->gprs[4] = (__force __u64) &frame->uc;
408 regs->gprs[5] = current->thread.last_break;
409 return 0;
410 }
411
412 /*
413 * OK, we're invoking a handler
414 */
415
handle_signal32(struct ksignal * ksig,sigset_t * oldset,struct pt_regs * regs)416 void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
417 struct pt_regs *regs)
418 {
419 int ret;
420
421 /* Set up the stack frame */
422 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
423 ret = setup_rt_frame32(ksig, oldset, regs);
424 else
425 ret = setup_frame32(ksig, oldset, regs);
426
427 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
428 }
429
430